Scribing apparatus



Dec. 2, 1958 P. MAURER ETAL 2,862,300

SCRIBING APPARATUS Filed March 22, 1956 6 Sheets-Sheet 1 I N V EN TORS F/ER'RE MA U/PER 5 BY JassFw U/MAL/RU Dec. 2, 1958 P. MAURER ETAL SCRIBING APPARATUS 6 Sheets-Sheet 2 INVENTORS W L/USEF'H U/MAL/RU l) TOfA/EY Dec. 2, 1958 P. MAURER ET AL 2,862,300

SCRIBING APPARATUS Filed March 22, 1956 e Sheets-Sheet 3 INVEN TORS F/EHFE MAUREA A/055 D/MA um? 7' ram Vi Y Dec. 2, 1958 v P. MAURER ET AL 2,862,300

SCRIBING APPARATUS Filed March 22, 1956 6 Sheets-Sheet 5 INVENTORS PIERRE- MA UR'ER BYL/USEFH D/MAu/m 47' Ole/VA Y United States Patent 2,862,390 FB IN A P RA U Application March 22, 1956, Serial No. 573,235 12 Claims. ((1313-41) This invention relates. to the art of making pellets of relatively small, thin material suc as are used in transistors, semiconductor devices, and like.

A principal' object of the invention is to provide an improvedmechanism .for scribing or subdividing a wafer of semiconductor material to form therefrom a multiplicity of individual subdivisions or pellets of accurately controlled dimensional conformation.

Another object is to provide an improved mechanism for scribing a wafer-like member simultaneously .along a plilrality .of parallel scoring line s, together with means for rapidly selecting and determining the spacing between adja cent lines tobe scored.

A further object is to provide an improved apparatus for scribing or subdividing a crystal material into a multiplicity of square, rectangular or other shaped pellets.

A feature of the invention relates .to a machine for scoring or scribing a hard material such as a semiconductor crystal, and including in the mechanisrn'a plurality of scribing tools arranged in staggered pairs, in conjunction with a selector ,mechanismcommon to all the tools for rapidly determining which sets of tools are to be placed in eifective scribing relation with the surface of the material to .be scribed.'

Another feature relates to a novel selection control mechanism for a multi-unit cutting or scoring head, whereby the units of the cutting head can be selectively actuated to cutting or scribing position by a'selecting mechanism of .the permutation cross-bar .kind.

A further feature relates to a machine for efiecting simultaneous multiple scoring orscribing of crystal wafers of germanium or other semiconductor material, whereby uniformity of dimensional conformation can be obtained in the production of subdivided pellets of the gcrystal, while decreasing the time and expense which are involved in the .use of conventional single-line scribing orfs corihg apparatus. i w

A further feature relates to the novel arrangement and relative location and interconnection of parts' vvhich cooperate to provide an improved machii e for scribing, scoring, or cutting rectangular, square or o ther shape pellets of transistor crystal material and the likj whereby various sizes of pellets can be produced in mass production at relatively low cost. i i I J Other features and advantages will be apparent from the ensuing descriptions, the appended claims and the drawing. i i i In the drawin which shows by wavof example one preferred embodiment, i

Figs. 1, 2 and 3 represent inplan view, in approximately twice actual size, three typical pelletsof semiconductor crystal material produced according to the invention; Figs. 4, 5 and 6 'are schematic plan views ,of three .differeiit relations of the scribing of scoring lines prcduced according to the invent on; i i i Fig. 7.is an ometric perspective view of a machine ass ins t th niee iq i;

. crystals is an important element;

2,862,300 Pate d Dee 2, 95s

Fig. 8 is an isometric perspective View of part of the scribing tool adjusting and selecting mechanism of Fig. 7

Fig. 9 is an isometric perspective view of the cross-bar permutation selector mechanism of Fig. 7;

Fig. 10A is an isometric perspective view showing one setting of the selector bars;

Fig. 103 is a similar isometric perspective view showing a different setting of the selector bars;

Fig. 11 is a schematic diagram explaining the operation of the scriber selector mechanism;

' Fis- 2.,i an isometri Per cti e ew of t n rm izing or permutation bar restoring mechanism of Fig. 7;

Fig. 13 is a plan View of part of the machine to show more clearly the manually operated lever arrangement for the selecting mechanism.

As is well known, the manufacture of such devices as transistor pellet-s has been relatively expensive because of the requisite fineness and precision work involved in the making of such pellets. ,One of theexpensive operations is that of cutting a relatively large and thin portion ,of a crystal, usually in .the form of a crystal wafer of germanium or other semiconductor material, into a multiplicity of relatively small pellets of uniform dimensions. Previous crystal cutting mechanisms are not always feasible for that purpose because of the peculiar physical characteristics of the semiconductor crystal material. Amongst these characteristics of the material are its hardness and the likelihood of fracturing along non-linear lines. Furthermore it is important in certain cases to be able to scribe or cut recta gular 'or square pellets in difierent bitches of different dimensional sizes. Where a single scrihing or scoring tool is used to produce the scoring lines on the crystal surface, it is necessary to index the single tool to the various successive positions which determine the spacing between the successive scoring lines. 'This usually involves a complicated and expensive gauging mechanism to make sure that the spacing 'betweenithe successively scored lines is always the same. In accordance with the present invention this difiiculty is overcome by using a multiplicity of pairs of scoring tools which are arranged in staggered columnar array, togetherwit-h a uovelselecting mechanism of the generic cross-bar permutation kind for determining which sets of scribing tools are to ,be efieetive in the scribing operation.

Merely for illustration there is shown in Fig. 1 of the drawing, in approximately double size and in plan view, a square crystal pellet which may be produced according to the invention. In certain cases it may be desirable to change the spacing of the scoring lines to produce rectangular crystals, such for example as'the crystal shown in Fig. 2. Likewise it may be'requiredto produce a rectangular crystal of longer length, such as shown in Fig. 3. With ordinary single scribing tool mechanisms the time and expense involved in changing the mechanism for scoring or scribing for the different sizes and shapes of However, accordingto the present invention the time and expense necessary to, change from one line scoring relation to another is greatly redunced.

For example, taking as an illustration a wafer 10 of germanium or other semiconductor material of approxi mately three-,quar-ters'to one inch in diameter, asshown double actual size in Fig.4, the wafer '10 may be scored simultaneously in a series of parallel lines extending parallel to one diameter of the wafer, as indicated by t he' numeral 11. 'The'wafer is then turned through an angle of and the wafer is again scored in ase ries of paral lel lines12 extending at right angles to the lines ll. results in the formation of square scored boundaries so that the wafer can then be subjected to any subsequent cutting or fracturing operation along the scored or scribed lines with the assurance that the wafer is accurately subdivided into square pellets.

In other cases it may be necessary to produce pellets such as shown in Fig. 2 wherein the length is approximately twice the width. For that purpose the wafer 10, as shown in Fig. 5, is scored along the parallel lines 11 by all the scoring tools. The wafer is then turned through an angle of 90 and only a selected set of scoring tools is rendered effective by the selecting mechanism according to the invention, so as to score the lines 12 at twice the spacing as that between the lines 11.

Similarly, by choosing a different set of scoring tools any desired ratio of length to width of the scored boundaries in the wafer can be selected. Thus, as shown in Fig. 6 the lines 12 are simultaneously scored with a spacing that is approximately three times the spacing of the lines 12 in Fig. 4, thus producing pellets of a three to one rectangular ratio as shown in Fig. 3. It will be understood, of course, that the invention is not limited to any particular ratio of length to width of.the scored boundaries. However, by using a fundamental interval between the staggered scoring tools it is possible to select with rapidity any desired integral ratio of length to width. For example, relatively large squares may be scored. A spacing may be provided between all adjacent lines which is twice or three times the spacing shown in Fig. 1.

Referring more particularly to Fig. 7 of the drawing, the mechanism according to the present invention comprises a bed plate 13 which can be attached by suitable lugs 14 and bolts (not shown) to any stationary table or support preferably, although not necessarily, having a horizontal surface. The upper face of bed plate 13 is provided with a longitudinal groove 15 having tapered side walls and in which is slidably movable a machine slide 16. The under surface of slide 16 has attached thereto a rack 17 located in a central longitudinal recess 18 in the bottom of groove 15. Rotatably mounted in the bed plate 13 is a shaft 19 carrying at one end a pinion 20 which meshes with the rack 17 to effect longitudinal sliding motion of the slide 16. For that purpose the shaft 19 may have attached thereto a suitable hand wheel 21.

is a stationary frame 22 which supports the scribing mechanism to be described. The frame 22 has a channel 23 in which are located a series of similar units for controlling the depth of the cutting or scoring by the respective scoring units. Only one of these depth control units is shown in Fig. 7 and is designated generally by the numeral 24. Frame 22 has an additional channel 25 in which are slidably mounted a set of three permutation selector bars 26, 27, and 28. The bars 26, 27, and 28 are provided with aligned slots 5 through which project the fixed pin 6 (Figs. 9 and 13) to limit the sliding movement of the bars in either. direction. One or more spring-pressed friction members 7 resiliently press against the bars to exert a frictional drag thereon. The three bars are normally at their extreme right hand position where the stop pin 6 engages the left hand end of the slots 5. In accordance with the invention the bars 26, 27 and 28 are selectively operated to three different combinational settings in accordance with the desired spacing between the scoring lines to be effected on the surface of wafer 10. In one such combination all of the three bars 26, 27 and 28 are moved simultaneously as a unit from their normal position, to the left. This movement of the three bars is effected by a pin 29 which is arranged to be moved against the right hand ends of the three bars, the pin 29 being provided with a suitable hand-operated lever 30 (Fig. 9). In the second combinational setting of the bars, bars 26 and 27 are operated as a unit towards the left, as seen in Fig. 7, while bar 28 is held stationary. This selective simultaneous operation of the two bars 26 and 27 is effected by a pin 31 which is fastened to bar 26 and extends forwardly of that bar to be engaged by a Rigidly attached to the bed plate 13 on its upper face suitable hand-operated lever 32. The pin 31 also extends through a slot 33 (Figs. 10A and 10B) in bar 27. In the third combinational setting, only the two bars 27, 28 are operated. For that purpose the bar 28 has fastened thereto a pin 34- which extends rearwardly ofbar 28 so as to be engaged by a suitable hand-operated lever 35. The pin 34 carried by bar 28 also extends forwardly into a slot 39 in bar 27 It will be understood that the operating shafts 36, 37, 38, for the respective levers 30, 32, 35, extend forwardly to a convenient point in front of the bed plate 13 and each shaft has a respective turning knob or handle 36a, 37a, 38a and a respective tension spring 36b, 37b, 38b (Fig. 13) for biasing them towards the right.

In the normal position of the three bars, the pin 34 is at the left hand end of slot 39, while pin 31 is at the left hand end of slot 33. As will be clear from the showing of Figs. 10A and 10B, if it is desired to move the three bars simultaneously, the lever 30 is operated. This causes the pin 29 to engage the ends of the three bars so as to move them simultaneously to the left. If only the bars 26, 27 are to be moved, lever 32 is operated, with lever 32 directly engaging pin 31 fastened to bar 26. Pin 31 in moving to the left engages the left hand end of slot 33 and moves the bar 27 in unison with bar 26. Bar 28 remains stationary since its operating pin 34 is stationary. If the bars 27 and 28 only are to be moved, lever 35 is operated and it directly engages pin 34 fastened to bar 28. Pin 34 in moving to the left engages the left hand end of slot 39 and moves bar 27 as a unit with bar 28. Bar

26 remains stationary since its operating pin 31 is now stationary.

Each of the bars 26, 27, 28 has on its upper edge a series of camming teeth 40 arranged in permuted spaced relation. Each tooth has sloping faces 41 and a flat top face 42. In the particular machine shown, the camming teeth 40 are located on their respective bars so as to define thirteen different selective settings designated 1-13 (see Figs. 9 and 11). In the normal position of the three bars 26, 27, 28, there is at least one camming tooth located at each of the thirteen positions.

Extending transversely of bars 26, 27, 28 are thirteen equally spaced parallel cross bars 43 (Fig. 7) and schematically represented in Fig. 11 by the dotted lines for each of the thirteen positions. Each of these cross bars is constituted of a spindle 44 which is joined to a threaded shank portion 45, preferably through a ball socket joint or the like so as to permit each spindle to be raised and lowered slightly without disturbing the position of the associated threaded shank 45. Cross-bars 43 are mounted for sliding movement in the direction of their length in the frame 22 attached to the bed plate 13. Each of the openings 70 in the frame 22 through which the corresponding spindle 44 passes has substantially the same diameter as the diameter of the spindle to allow the spindle to turn.

The threaded shank portion 45 of each cross-bar is threaded through the rear wall 46 of the frame 22 and is provided with an adjusting head 47 so that by turning the head 47 the corresponding spindle 44 can be adjusted forwardly or rearwardly with respect to the slide 16. A suitable locknut 48 is provided on each shank 45 to locate the associated spindle in its adjusted forward position. Each spindle 44 has a corresponding pivot block 49 which constitutes part of the depth control unit 24 mentioned above. Block 49 carries a pin 50, the rearwardly extending portion of which overlies the bars 26, 27, 28 and is urged into spring-pressed contact with the upper edges of those bars by means of a tension spring 51 which is connected at one end to pin 50 and at the opposite end to a pin 52 (fixed to the frame 22). Threaded transversely through each pivot block 49 is an adjusting stop screw 53 which passes through the pivot block so as to engage the upper end of a vertical extending stop 54. A suitable locknut 55 is provided for screw 53. The setting of the stop screw 53 against stop 54 determines the cutting depth .of a cutting stylus -57. to be .described.

Pinned or otherwise fastened .to the free .endsof. each spindle 44 he scribing :head .designated generally :by [the numeral 56 and fastened toxeach head is .a downwardly depending stylus 57 terminating in a diamond point 58 which is adapted to contact the upper surface .of the crystal wafer 10. Ifthecrystal wafer is .of circular shape, for example .of about one inch in diameter, it is seated in .a suitable vacuum-operated chuck 59 which is fastened to the slide 16 and connected through a flexible tube 60 (Fig. 7) or through a sliding valve to a suitable vacuum .pump .(notshown) so as to maintainthe wafer 10 firmly seated horizontally in the chuckr5-9 but with .the upper surface of the wafer above the margin of the chuck. Furthermore, the chuck should .be so designed that its upper margin is well below the diamond points 58 of the various scribin'g heads when those heads are intheir lowermost or scribing .position.

it will be understood, ofcourse, that the invention is not limited to the scribing of circular -wafers, square or rectangular wafers may be scribed, for-example, provided they are held in the chuck 59 against relative turning during each scribing operation. The chuck 59 is-rotatably mounted in'its carrier 61 and is provided with a suitable handle .62 for turning it through any desired angle, for example an angle of 90 to effect the intersecting scribed lines 11 and 12l(see Figs..4, 5, 6:).

The above-described selecting mechanism for the thirteen spindles .44 is duplicated at the forward part of the machinean'd includes a set of three permutation selector bars 26a, 27a, 28a similar in construction to the corresponding bars 26, 27, 28 at the rear of the machine. These bars are diagrammatically illustrated in Fig. 11 wherein the bars are shown in their normal positions.

The bars 726a-28a are slidably mounted in a frame (not shown) similar to frame 22. Also slidably mounted in this latter frame for cooperation-with the selector'bars 26a-28a is an additional set of thirteen spindles 44a with their respective scribing heads 56a and with their respective depth control units 24a. Each of these scribing heads in the forward unit also includes a stylus 57a terminatin'g in a corresponding diamond point 58a. Each of the spindles 44a is provided-with a threaded shank 45a for adjusting the corresponding spindle in the direction of its length while permitting the spindles 44a to'be raised and lowered by engagement with the camming teeth 40a on the bars 26a28a. The shafts 36, 37, 38 which, as above described, selectively operate the rear bars 2648, are also coupled to the corresponding forward bars 26a 28a to set these bars in unison with the corresponding bars 26-28 of the rear set. In general it will be seen, therefore, thatthe elements of the selecting mechanism at the front part of the machine are identical in structure and operation with the corresponding selecting elements at the rear \of the machine and for that purpose they bear the same designation numerals with the suflix a.

Preferably each of the spindles 44 in the rear set is in longitudinal alignment with the corresponding spindle 44a of the front set. However, the scribin'g heads 56 on their respective spindles 44 are staggered with relation to each other as schematically illustrated in the upper half of Fig. 11 so that their respective diamond points 58 trace equally ,spaced scribing lines on the surface of the wafer 10 as the wafer is moved beneath the diamond points, as indicated by the arrow in Fig. 11. These thirteen equally spaced lines are only scribed if all the thirteen heads 56 are in their lowermost position, in other words if all their pins 50 are in engagement with the nontoothed edges of the bars 26-28. Merelyfor explanation, Fig. 11 shows the various parts in exaggerated dimensional spaced relation. Actually, however, the dimensions are such that for example when all the scribing heads are in their lowermostscribing positions, the spac- 6 ing between the scribed lines may be'a fundamental interval, forexample .045 inch.

'Similarly'the forward set of scribing heads 56a if they are all in their lowermost scribing positions will trace corresponding equally spaced scribing lines on the other half of the surface of the wafer 10. However, in .order to avoid duplicate overtracirig of the same line the number one spindle 44a of the forward set is blank or in other words carries no scribing head. However the second through the thirteenth spindles 44a of the forward set carry respective scribing heads 56a with respective diamond points 58a, these latter heads being staggered as indicated in 'Fig. ,11 so that .when all the heads 56a of the forward set are in their lowermost position they trace twelve equally spaced scribing lines on .the other half of the wafer 10.

It will be clear, therefore, that if all the scribing heads ofboth the rear andforward units are in their lowermost or scribing positions the wafer 10 will be scribed with twenty-five equally spaced lines approximately .045 inch apart. This scribing position is effected by moving all the bars 2628 and 26a+28a to the left .by means of the hand operated shaft 36. As will be clear from Fig. 11, under this condition none of the teeth 40 or 40a is located beneath a scribing head spindle 44 or 44a with the result that allthe-spindles assume their lowermost position with their diamond points in scribing engagement with the surface of the wafer 10.

If ,it is desired to scribe equally spaced lines having doublethe fundamental spacing, for example .090 inch, thenthehand opera-ted shaft 38 is operated thus moving bars 217, 28, 27a, 28a to the left and permitting the odd numberedspindlesdi, 4.4a to drop into scribingrelation with the v /afer 10. If it is desired to scribe the wafer withequally spacedlines of triple the fundamental spacing, for example .135 inch, that can bedone by operat ing the hand operated shaft 37 causing bars 26, 27, 26a, 27a to moveto thejleftand thus allowing only the first, fourth, seventh, tenth and thirteenth scribing heads to be lowered: into scribing relation with the wafer 10. It will be-clear from the foregoing, therefore, that it is possible merely by threeselective operations of the shafts 36, 37 and 38to set the scribing'heads rapidly in the proper relation to scribe lines ofdiiferent fundamental spacings and of course by means of the micrometer screw shanks 45 these spacings can be initially preset to a high degree of accu a y .After the wafer 10 has been thus scribed with the parallel lines ;,11, the chuck 59 is turned, for example, through and the various scribing heads are set in the desired scribing combinations depending upon what particular shape of individual pellet size is required. For example if the pellet size is to be .045 inch square, as

shown in .Fig. \l, then of course the first set of lines 11' will: be scribed with all-the scribing heads in scribing relation and then when the chuck 59 is turned through 90 and the wafer is subjected tothe second scribing operation,;all the scribing heads are also in there lower scribing position. {1" his results in the scribing of a multiplicity of equalsquares onthe surface of the wafer. If, however, .a rectangular shape as shown in Fig. 2 is required for .the finalpellets after scribing the lines 11 with all the scribing heads down, then the chuck 59 may be tumqd i fough an angle of 90 and only the odd scribing h ads-may belowered, this resulting in a multiplicity of identical scribed boundaries .045 inch by .090 inch.

If, howeventhe rectangular shape shown in-Fig. 3 is requirefdwhen the secondset of lines 12 is to be scribed, only the first,.fourth, seventh, tenth and thirteenth scribing heads in each set are lowered, resulting in a multiplicity of identical rectangular scribed boundaries .045 f y 1 It rivilhbeunderstood, of course, that in scribing the first set of lines 1 1 in the wafer the hand wheel 21,is turned to'traverse the slide 16, for example toward the right, until the wafer is scribed completely along one dimension. After the first scribing operation is completed the scribing heads may be raised to their non-scribing position. For that purpose the slide 16 carries a trip finger 63 which is adapted, at the completion of each scribing stroke, to engage a roller 64 carried by lever 65 attached to shaft 66, which shaft extends transversely above both sets of bars 26-28, 26a-28a. All of these bars have aligned notches 67, 67a in which ride corresponding pins 68, 68a carried by arms 69, 69a, which are also attached to shaft 66. Thus at the end of each scribing stroke all the selected bars are restored to their normal position wherein all the scribing heads are in their raised positions. The hand wheel 21 can then be turned counterclockwise (Fig. 7) to return the slide 16 to its normal position, whereupon the chuck 59 can be turned through 90 and locked in that position by means of the handle 62. The desired scribing heads for the second set of lines may then be selected by the appropriate selective resetting of the bars 26-28 and 2611-2811 whereupon the hand wheel 21'can be turned clockwise to effect the next scribing operation.

It will be understood, of course, that the invention is not limited to any particular number of scribing heads, and a greater or less number than those mentioned may be employed. Likewise other changes and modifications can be made in the apparatus described consonant with the scope of the appended claims. Furthermore, while it has been mentioned that the chuck 59 can be turned to two different locked positions to effect right-angled intersection scribings, it will be clear that if diamond shapes are to be scribed the chuck can be turned to and locked in the corresponding appropriate setting. Likewise if desired the chuck may be manually turned during one or both scribing traverse to trace specially shaped contours for the scribing lines.

What is claimed is:

l. A machine of the kind described, comprising means to hold an article whose surface is to be scribed in parallel lines, a plurality of scribing devices for tracing said lines, means to move said article past said scribing devices, said devices being mounted in staggered columnar array, and means for selectively operating said devices into scribing relation with said surface, the last-mentioned means including a plurality of permutably settable selector bars, and means to set said bars for simultaneously selecting a desired combination of said devices whereby said surface can be scribed with equally spaced parallel lines and Lvith the said spacing determined by the setting of said ars.

2. A machine of the kind described, comprising means to hold an article whose surface is to be scribed in parallel lines, a plurality of scribing devices, means to move said holding means past said devices to trace said lines, a plurality of supports one for each device, means to adjust said supports to locate each device in a direction transverse to the direction of movement of said holding means, said devices being mounted on said supports in successive staggered columnar array, selector bar means normally engaging said supports to hold said devices out of scribing contact with the surface of the article, means to operate sa1d selector bar means in combinations to cause a corresponding plurality of said supports to be moved and thereby moving the associated scribing devices into scribing contact with said surface, and means connected to said bar means for simultaneously selecting a desired combination of said devices whereby said surfacecan be scribed with equally spaced parallel lines and with the spacing between adjacent lines determined by the setting of said bar means;

3. A machine according to claim 2, in which each of saidsupports is provided with a respectiveadjusting means to control the depth of the-line scribed by the associated scribingdevice in the surface of the article.

4. A machine of the kind described comprising a re ciprocable slide, means to fasten to said slide. anarticle whose surface is to be scribed in spaced parallel lines, a plurality of parallel spindles extending transversely to said slide, a scribing device carried by each spindle, means connected to each spindle for vertically moving the scribing device carried thereby into and out of contact with the article, means to adjust each spindle transversely to said slide, a group of slidable bars having respective combinations of camming surfaces for operating said spindles in selected combinations to determine the selection of said devices for scribing said lines, and means connected to said bars for simultaneously selecting a desired combination of said devices whereby said surface can be scribed with equally spaced parallel lines and with the spacing between adjacent lines determined by the setting of said bars.

5. A machine according to claim 4, in which the means for adjusting each spindle transversely of said slide comprises a micrometer screw connected to each spindle, and means to lock each screw and spindle in transverse adjusted relation to said slide while allowing the spindles to move their respective scribing devices into and out of contact with said article.

6. A machine according to claim 4 in which the fastening means for the article on said slide includes a vacuumoperated chuck.

7. A machine according to claim 6 in which said chuck is provided with means to turn it to two different positions at right angles to each other whereby the article can be scribed with mutually perpendicular lines.

8. A machine of the kind described, comprising a fixed frame, means slidably mounted on said frame to hold an article such as a crystal wafer whose surface is to be scribed with a series of parallel lines, a member anchored to said frame and having a plurality of spaced parallel passageways extending transversely to the direction of sliding movement of said holding means, a plurality of spindles one in each of said passageways and arranged for adjustment lengthwise of the passageway, an adjusting screw coupled to one end of each spindle, a scribing device carried by the other end of each spindle, means to turn each spindle and thereby to bring the associated scribing device into and out of scribing contact with the surface of said wafer, the last-mentioned means comprising a group of slidable bars each having on one edge a series of spaced camming teeth, means carried by each scribing device and engaging said one edge of each of said bars, and means to operate said bars in selected combinations to bring the teeth on one or more bars into registry with the said means carried by each scribing device and thereby to determine which of said scribing devices are moved into scribing contact with the said surface of said wafer.

9. A machine of the kind described, comprising a fixed frame, a first group of selector bars slidably mounted at one side of said frame, a second group of selector bars slidably mounted at the other side of said frame, a single set of operating shafts coupled to bothf groups of bars to set them in permuted combinations,

a first set of spindles each carrying a pointed engraving stylus and arranged in staggered columnar array, a second set of spindles each carrying a pointed engraving stylus and arranged in staggered columnar array, a pivot block attached to each spindle for raising and lowering the associated stylus with respect to an article to be engraved, a slide, means to move said slide transversely to said spindles, an article holding chuck carried by said slide, each of said bars having a series of camming projections which are arranged to be engaged by said pivot blocks to raise the associated styluses out of contact with the said article in the chuck, and means for selectively operating said shafts to set simultaneously selected bars 10. A machine according to claim 9 in which the said bars are arranged to be moved to different combinational settings and thereby to cause said styluses to engrave equally spaced parallel lines in the surface of said article with the spacing between lines different for each such combinational setting.

11. A'machine according to claim 9 in which adjustable means are provided for each pivot block to control the depth of the engraving by said styluses.

12. A machine of the kind described, comprising means to hold a crystal Wafer to be scribed with equally spaced parallel lines, a set of at least seven scribing styluses arranged in staggered columnar array, slidable bar selector means to be variously set to determine which styluses are to be moved into scribing contact with said Wafer, means to operate said bars to one setting whereby all the styluses are moved into Contact with the wafer,

10 means to operate said bars to another setting whereby only alternate styluses are moved into contact with the Wafer, and means to operate said bars to a third setting whereby the first, fourth and seventh styluses are moved into scribing contact with the wafer.

References Cited in the file of this patent UNITED STATES PATENTS 477,585 Wilson June 21, 1892 668,944 Wilmans Feb. 26, 1901 1,198,402 Bagnall Sept. 19, 1916 1,834,143 Callard Dec. 1, 1931 2,064,243 Campbell Dec. 15, 1936 2,081,439 Simmons May 25, 1937 2,158,900 Goflfaux May 16, 1939 2,377,098 Owen May 29, 1945 2,515,076 Brichard July 11, 1950 

